Forward looking RGB/optical coherence tomography duplex imager

ABSTRACT

Systems, methods, and devices for directed to duplex imaging techniques for combining high-resolution surface images obtained with a Scanning Fiber Endoscope (SFE), and high-resolution penetrating OCT images obtained through Optical Coherence Tomography (OCT), from a SFE, and interleaving frames to improve resolution and identify below surface information of biological structures.

BACKGROUND

Chronic Total Occlusion (CTO) refers to a complete obstruction of thecoronary artery. CTOs can result from coronary artery disease anddevelop due to atherosclerosis. The blockage prevents all downstreamblood flow, and can cause a range of symptoms and issues, includingchest pain and heart attacks. In some patients, however, CTOs cause nophysically identifiable symptoms, e.g., silent heart attacks, and theCTOs go undiagnosed. Many patients with CTO also do not receive therapydue to practical difficulties of penetrating the occlusion withpartially complete angiographic images.

Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT)are two current methods for inter-coronary imaging. IVUS traditionallyutilizes a catheter with an ultrasound probe on a proximal end andprovides a cross-sectional view of blood vessels. OCT operates similarlybut utilizes the longitudinal partial coherence of light rather thantime delay of sound waves, to obtain information from reflected,scattered light. OCT can provide resolution on the order of micrometers,but its penetration depth is often limited to several millimeters belowtissue surface. Both IVUS and OCT provide only a radial visualization atthe imaging location. This requires the imaging device to pass by theocclusion to image it. When applied to arterial imaging and diagnosingCTO's, for example, these techniques can provide cross-sectionalinformation of the vessel, such as, indications of narrowing in theartery, e.g., due to plaque build-up, but cannot provide informationbeyond the position of their side scanning sensors within the vessel.Therefore, when a CTO or other blockage is present, current IVUS and OCTprobes must penetrate the occlusion before any CTO visualization ispossible.

Penetration of the occlusion is often the blocking step to being able tocomplete therapy such as placing a stent. Penetration with a guidewire,for example, can be very time-consuming, e.g., 30 minutes or more, andin some cases, penetration is not possible. Accidentally exiting thelumen with the guidewire poses an additional risk, as doing so can causesignificant damage to the patient. As such, it would be advantageous tohave the ability to identify and visualize an occlusion prior to andduring the penetration procedure.

Scanning Fiber Endoscopes (SFE) can provide color imaging based on RGBreflectance, and wide-field viewing of the internal arterial region andproximal CTO. SFE imaging techniques only provide surface informationwithin the artery and of the proximal end of the CTO. The inventionherein combines forward looking RGB reflectance images combined withforward penetrating sectional images of CTO using OCT.

SFE probes scan at approximately 10 kHz for RGB imaging, which providesa single revolution time of about 100 μs. This rotation leaves littletime for any OCT scan. Scanning with OCT while changing the location ofthe scan this quickly would cause the OCT image to be useless fromexcessive lateral motion artifact. OCT imagers require 7-8 μs imagingtime per line and deliver a 100 kHz A-line acquisition speed. At thisrate, during one spiral rotation, only 10 A-line samples can beobtained, thus resulting in poor OCT lateral resolution due to probemovement artifact during the wavelength-sweep and a lack of A-lines tocompose the penetrating B-mode image. To reduce the rotational speed ofthe SFE probe, significant modifications are required to be made, e.g.,changing the length of fiber inside the SFE, but such changes are oftennot adequate for RGB imaging, causing slow frame rates and larger rigidlength of the RGB imager.

SUMMARY

Systems, methods, and devices for improving Forward looking OCT imagingtechniques combined with forward looking SFE surface images. The presenttechnology can provide a forward viewing direction, useful for variousmedical applications and identifying cross-sectional information ofbiological structures, such as Chronic Total Occlusions.

In embodiments, systems and methods can comprise a probe for RGB surfaceimaging and optical coherence tomography (e.g., a scanning fiberendoscope), the probe being electronically configured to obtain (1)frames of surface images, and (2) orthogonal penetrating images along animage plane defined by a line on the surface image. At least onecomputing device can be operable to obtain A-line scans at a pluralityof points along the scanning path where a speed of the probe is at aminimum and to construct at least one frame having B-mode images fromthe plurality of A-line scans.

In various embodiments, a plurality of B-mode images offset by ascanning angle can be compiled and interleaved to constructthree-dimensional images.

As discussed herein, the present invention can be applied to variousmedical applications, including but not limited to scanning and imagingwithin a blood vessel lumen to identify at least one of an occlusion, adefect within an occlusion, a calcification, adventitia, a microchannel,or other features within a vessel or the body.

BRIEF DESCRIPTION OF THE DRAWINGS

The combination of the two imaging modalities and other features of thepresent disclosure will become more fully apparent from the followingdescription and appended claims, taken in conjunction with theaccompanying drawings. Understanding that these drawings depict onlyseveral examples in accordance with the disclosure and are, therefore,not to be considered limiting of its scope, the disclosure will bedescribed with additional specificity and detail through use of theaccompanying drawings.

In the drawings:

FIG. 1(a) illustrates a forward looking SFE image with an RGB image of ahuman finger shown in the inset.

FIG. 1(b) illustrates several line scans where, using methods describedherein, OCT penetrating image of a cross-sectional “cutaway image” canbe displayed. Thus, the system herein can scan with a spiral raster scanor can scan with line scans as shown in FIG. 1(b).

FIG. 1(c) illustrates a cross-sectional image plane that can be selectedelectronically relative to the RGB surface image.

FIG. 2 illustrates a block diagram of a duplex imager capable of RGBsurface images and OCT penetrating images in accordance with embodimentsdescribed herein.

FIG. 3 illustrates a duplex image system inserted into a lumen 310.Display 320 illustrates duplex imager having RGB surface image and OCTpenetrating image of a CTO 330.

FIGS. 4(a) and 4(b) illustrate two methods of constructingthree-dimensional images from the OCT penetrating image frames, withFIG. 4(a) illustrating a method using acquired planes, and FIG. 4(b)illustrating a method using reconstructed slices.

FIG. 5(a) illustrates a normal, slowly scanned OCT image and FIG. 5(b)illustrates a simulated compounding image.

FIG. 6 illustrates the critical method to scan and acquire the OCT modepenetrating scan, during one frame of normal use for a surface RGBimage.

FIG. 7 illustrates a relationship between lateral resolution and aradius of a B-mode scan.

FIG. 8 illustrates absorption coefficients of tissue constituents forvarious wavelengths.

FIG. 9 illustrates an example computing environment in accordance withembodiments discussed herein.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative examples described in the detaileddescription, drawings, and claims are not meant to be limiting. Otherexamples may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presented here.It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in theFigures, may be arranged, substituted, combined, and designed in a widevariety of different configurations, all of which are explicitlycontemplated and make part of the present disclosure.

The present disclosure relates to duplex imaging techniques. Moreparticularly, the present disclosure combines high-resolution surfaceimages obtained with SFE, and high-resolution penetrating OCT imagesobtained through Optical Coherence Tomography (OCT), from a ScanningFiber Endoscope (SFE), and interleaving frames to improve resolution andidentify below surface information of biological structures. As appliedto CTOs, SFE high resolution color imaging technology combined withforward-looking OCT, allows visualization of occlusions, andvisualization below the surface of the occlusion prior to penetration.In addition, micro channels, calcifications, and adventitia can beimaged to provide additional clinical benefits and information. With theforward-looking imaging, a physician can, for example, identify and moresafely penetrate the CTO, using a guidewire or other means, and identifya CTO's location and strong or weak aspects (calcification ormicrochannels) prior to penetration. Aspects of the invention furtherprovide the ability to acquire three-dimensional (3D) OCT data. Thus,combining SFE and interleaved frames of an OCT can provide a forwardviewing direction and cross-sectional information of the CTO.

The present invention can utilize certain OCT A-line acquisitions toconstruct frames of compounded B-mode images to identify a subsurfacetissue information. FIG. 1(b), for example, identifies possible B-modescanning angles, as indicated on a Cartesian plane with the straightlines, each input can be represented by a sinusoidal wave, and the phasedifference between the inputs control the motion of imaging scans, whichare typically linear. Note that OCT images are gathered only when thelinear scan reaches the maximum amplitude and minimum velocity, thisallows excellent OCT lateral resolution. This slow motion is like themomentary lack of motion when a child's swing reaches max height andreverses direction.

There are also frames of spiral surface mode scans depicted in FIG. 1.These form a raster scan to scan the surface of the scene in front ofit. Note that the surface speed of the scanning is very high and would“smear” the OCT scans, thus the spiral scan is used for OCT only.

Moreover, by combining B-mode scans from various rotational angles, acone-shaped three-dimensional image can be obtained. The 3D data can bevisualized in the form of multiple B-mode images acquired orreconstructed from various directions and angles.

FIG. 1(b) illustrates these principles and B-mode scanning angles withrespect to a cartesian coordinate plane. Based on the relative anglesbetween two inputs (X and Y) to the OCT probe, the overall probe motionwill vary. The cartesian plane and lines 110, 120, 130 (as more fullydescribed herein) are indicative of the probe's scanning angle withrespect to a top surface of an OCT image. In other words, the two inputsX and Y represent an oscillating movement of the probe with respect tothe imaging plane. The relationship between X and Y indicates theoverall scanning motion, which can result in imaging of a particulararea in a potential OCT field of view.

In a first example, FIG. 1(a) illustrates a forward looking SFE image ofthe surfaces of the anatomy facing the imaging SFE catheter. A spiralraster scan may be used to bend the SFE fiber using a cantileverresonance of the fiber stub within the SFE imager. An RGB image of ahuman finger, as an example of the anatomy that can be imaged, from anactual imager is shown in the inset. In the spiral surface scan mode ofFIG. 1(a), two orthogonal sinusoidal waves, X and Y, with the samefrequency, e.g., sin(aft) and cos(aft), can create a circular motion forimaging if the phase differences of the sinusoidal waves are 90° or π/2radians.

In another example shown in FIG. 1(b), OCT Penetrating Scan Mode 110 a,the phase difference is 0°, i.e., the phase for each input is the same,then the circular motion becomes a linear motion, as illustrated by line110 a in Quadrants I and III, and the corresponding graph 110 b whenX=Y. The angle is controlled via relative amplitude. The 130 a and 110 ascans differ only in amplitude, same phase.

In another example shown in FIG. 1(b), OCT Penetrating Scan Mode 120 a,a phase difference of 180° or π radians between each input, X and Y,also results in the scanning motion becoming linear, as represented byline 120 a in Quadrants II and IV, and corresponding graph 120 b. Inparticular, graph 120 b illustrates a relationship wherein X=−Y. Here,similar to the example of line 110 a and graph 110 b, the scanningmotion is linear, but in the opposite direction and in oppositeQuadrants. Scan angles are controlled by amplitude; the same phase shownis equal amplitudes.

FIG. 1(c) illustrates one such cross-sectional image plane that can beselected electronically relative to the RGB surface image, with thevarious scanning angles graphed on a Cartesian plane. The straight linesdepict planes of penetrating OCT images that are possible, the spiraldepicts the raster scan for the RGB surface image. These two imagemodalities occur by sharing frames in the 30 frame per second systemdisclosed herein. In effect one can have the RGB image and severalplanes of OCT “into the occlusion” images simultaneously. One could have28 frames of RGB and 2 separate OCT “cutaway” images per second. Theresultant user image pair is illustrated in the insets.

FIG. 2 illustrates a block diagram of an example duplex imaging system200 usable with one or more embodiments discussed herein. The diagramillustrates a scanning probe 202, such as an SFE, alternately performingboth RGB scans 205 and penetrating B-mode scans 210, along the linearline indicated on the RGB image 220. The B-mode scan 210 along thelinear line comprises collecting a plurality of A-mode informationobtained at the oscillation endpoints of the scan (See also FIG. 6). Thecollected information from the B-mode scan may be processed through oneor more computing devices (e.g., PC 240), interferometers (e.g.,interferometer 250), and spectrometers (e.g., spectrometer 255) toproduce the OCT image 230. The RGB scan 205 produces the RGB surfaceimage 220, which is created from RGB reflected light through thecollection fiber 214 of the scanning probe 202. The RGB surface image isprocessed by color separator 223, light detector 224, and digitizer 225and input to the RGB imager 290.

A plurality of OCT images obtained from linear scans taken at variousangles at the imaging location can be used to produce, athree-dimensional image, and/or information related to a forward-facingview from the end of the SFE.

In examples, surface-mode scans may be obtained from a spiral scanningfiber. As illustrated in FIG. 2, the scanning probe 202 may comprise anoscillating scanning fiber 211 activated by one or more actuators 212,one or more lenses 213 through which emitted light may be directed andfocused, and the collection fiber 214 to receive reflected light foranalysis. RGB light is able to propagate through the interferometerunaffected.

In OCT mode, the collected light may be first analyzed by at least oneinterferometer 250, which can help identify an origin and location ofreflected light. In embodiments, a reference arm 215 may be utilized toprovide a reference point for the interferometer 250, and additionalcomponents/systems such as an RGB laser 270, OCT Broadband Light Source280, and combiner 260 can further contribute towards theinterferometer's function.

From there, interferometer data, and additional spectrometer 255 datamay be passed to the computing system 240, which may comprise one ormore computing devices to perform additional processing with regard toeach obtained OCT image. Processing at PC 240 may comprise a B-modeconversion module 242, Fast Fourier Transforms (FFT) 244, a baselinesubtraction module 246 and a dispersion compensation 248. Thisprocessing can produce an OCT image 230.

FIG. 3 illustrates an example imaging operation within a blood vesselwhich may utilize the B-Mode imaging system 200. FIG. 3 illustrates aside view of a blood vessel lumen 310 containing an occlusion 330, anOCT scanning/imaging area 340, RGB scanned surface 360, and a display320 of the RGB SFE and OCT scanned area. A scanning probe 350, which maycomprise an oscillating scanning fiber as described herein, scansbetween width 360 to provide a forward-looking view within the bloodvessel. As discussed herein, this forward view, e.g., along the lengthof the lumen, of the RGB image 360 and the penetrating view of 340 canallow observation of the surface of an occlusion 385 and a penetratingview of the occlusion 390 prior to or during contact or penetration.

In the present example, the occlusion 330 contains a calcification 370and a microchannel 380 running through the occlusion. These features maybe identified in the display section 320, which illustrates an RGBsurface image 385 and a corresponding penetrating OCT image 390 along ascanning line 395 a. The OCT image 390 may permit observation of a firstview of the occlusion 330 which likely depicts subsurface microchannel380 as well as the calcification 370. The RGB image 385 permits asurface view of the occlusion 385. In other words, RGB images 385combined with OCT subsurface images 390 are forward-facing and cantherefore characterize and guide therapy upon occlusion 330 and othersurface and subsurface features, e.g., microchannel 380, within theviewable area in a manner not possible with either image alone.

OCT subsurface images are be obtained from a linear scanning motion.Each linear scan produces a fan-shaped OCT image 390, which can providedepth information, and be usable to identify one or more features beyondor within occlusions, blockages, and areas beyond surface-levelfeatures. The resulting B-mode image targets comprise a plurality ofA-lines orthogonal to the scanning path and typically have a fan shapesince the origin of the scanning probe 350 and its light point is asingle point oscillating between width 360. The imaging depth in thefan-shaped B-mode can be determined by one or more variables in the OCTscanning scheme, including but not limited to reference arm length,swept-source bandwidth, and wavelength resolution.

Multiple linear penetrating OCT scans may be obtained at various anglesacross the circular RGB image scanning area. For example, theillustrated linear scan line 395 a corresponds to the end view of theimage plane of OCT image 390. The scans along line 395 a produce OCTimage 390, which may contain information indicative of the occlusion330, calcification 370, and microchannel 380. Subsequent linear scansmay be obtained at the operator's command to the software, with eachscan line being rotated around a central point in the viewing area 360.

By composing the scanning patterns from various angles,three-dimensional images can be acquired. For example, using the variousangles, i.e., 0° to 180°, and scanning at intervals. If 15° intervalsare utilized, for example, twelve image planes can be obtained. FIG.4(a) illustrates this concept by generating three-dimensional data froma plurality of acquired linear planes. Since each obtained A-lineinformation contains information along the light source path, the imagehas path-dependency. That is, the images are affected by the reflectionof layers on the line of sight, and such data provides information toidentify the object structure from the image. In medical applications,for example the three-dimensional object structure can provide valuableinformation to a clinician, such as volume of a region. Additionally, avolumetric survey of the CTO can be performed to allow theinterventionalist to select the optimum crossing technique.

In another example, illustrated in FIG. 4(b), two-dimensional imageslices having path-dependency can be reconstructed to acquire thethree-dimensional structure. The sliced B-mode images can be obtainedfrom an arbitrary scanning angle from the scan origin. In this way,path-dependency between slices can be preserved.

FIG. 5(a) and FIG. 5(b) illustrate results of the above recursiveacquisition simulation. FIG. 5(a) illustrates an original OCT B-modeimage, wherein the image is slowly acquired using conventional OCT. FIG.5(b) is a simulated compounding image reconstructed using recursive dataacquisition. The image dithering in FIG. 5(b) is due to the simulatedscanner translation during an OCT wavelength-sweep. In both images, theinterval between A-lines are a 10-pixel distance.

FIG. 6 illustrates a B-mode edge scan and data acquisition scheme. Thesinusoidal scanning path 600 represents the area through which a probeand its light source are driven during a linear scan. During a B-modescan, the speed of the probe is at a maximum along center line 630, andat a minimum (i.e., zero speed) along the edge line 620 (during whichA-line acquisition occurs), which has an increasing, linear slope 640.Note the slow scan motion during acquisition (i.e., 5 μSec).

In OCT scans, a slowly moving scan position during A-line acquisitionsavoids distortions and smearing effects. Accordingly, in the currentmethod, A-line data is exclusively collected at the endpoints of theB-mode scan, where the fiber scan movement is slowest while it reversescourse. In this manner, data can be acquired at the most stable probeposition.

The present example of FIG. 6 illustrates 250 oscillations or spirals,during the OCT B-mode scan 610 resulting in 500 A-line acquisitionsalong endpoints of the scanning area. In OCT B-mode scans, the radius islinearly increased as the scan travels along linear slope 640. Graph 650enlarges a portion of an edge lie scan at a point where the A-line datais collected, and the probe movement is minimal. In an example, aconventional spectral domain OCT can take 5 μs to take an A-linespectrometer reading 660.

FIG. 7 illustrates a relationship between motion induced reduction oflateral resolution and the radius of a B-mode scan (defined as thedistance between the SFE probe and an imaging surface). The X-axisrepresents the B-mode scan radius (mm) on the imaging surface and Y-axisrepresents displacement of the probe during A-line acquisition time.Line 740 represents the probe's moving distance during A-lineacquisitions at each B-mode radius. For example, using a 5 microsecondacquisition window, at a 2.5 mm depth, the image would move 30 micronslaterally. Horizontal lines 710, 720, 730 represent lateral resolutionbased on a maximum B-mode scan radius. At a depth of 5 mm, representedby 710, the motion during acquisition would be 20 microns. Similarly, ata depth of 4 mm, 720, the motion during acquisition would beapproximately 15 microns, and at a depth of 3 mm, 730, the motion wouldbe approximately 12 microns. FIG. 8 illustrates absorption coefficientsof tissue constituents, applicable to various embodiments andapplications of the B-mode scans and methods discussed herein. SFEtransmits single mode laser lights for RGB and OCT imaging through theshared single mode fiber. The wavelengths of RGB are typically between400-700 nm and OCT is between 900-1300 nm. The appropriate single modefiber and OCT wavelength should be chosen to transmit both RGB and OCTin single mode without significant loss or mode changes (to multimode).FIG. 8 illustrates that in the 700-1100 nm wavelength range, the averageabsorption rate of materials is less than 10%, thus being particularlyapplicable for vascular applications.

FIG. 9 illustrates an exemplary computing environment in whichembodiments of the present invention is depicted and generallyreferenced as computing environment 900. As utilized herein, the phrase“computing system” generally refers to a dedicated computing device withprocessing power and storage memory, which supports operating softwarethat underlies the execution of software, applications, and computerprograms thereon. As shown by FIG. 9, computing environment 900 includesbus 910 that directly or indirectly couples the following components:memory 920, one or more processors 930, I/O interface 940, and networkinterface 950. Bus 910 is configured to communicate, transmit, andtransfer data, controls, and commands between the various components ofcomputing environment 900.

Computing environment 900, such as a PC, typically includes a variety ofcomputer-readable media. Computer-readable media can be any availablemedia that is accessible by computing environment 900 and includes bothvolatile and nonvolatile media, removable and non-removable media.Computer-readable media may comprise both computer storage media andcommunication media. Computer storage media does not comprise, and infact explicitly excludes, signals per se.

Computer storage media includes volatile and nonvolatile, removable andnon-removable, tangible and non-transient media, implemented in anymethod or technology for storage of information such ascomputer-readable instructions, data structures, program modules orother data. Computer storage media includes RAM; ROM; EE-PROM; flashmemory or other memory technology; CD-ROMs; DVDs or other optical diskstorage; magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices; or other mediums or computer storagedevices which can be used to store the desired information, and whichcan be accessed by computing environment 900.

Communication media typically embodies computer-readable instructions,data structures, program modules or other data in a modulated datasignal such as a carrier wave or other transport mechanism and includesany information delivery media. The term “modulated data signal” means asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in the signal. By way of example,communication media includes wired media, such as a wired network ordirect-wired connection, and wireless media, such as acoustic, RF,infrared and other wireless media. Combinations of any of the aboveshould also be included within the scope of computer-readable media.

Memory 920 includes computer-storage media in the form of volatileand/or nonvolatile memory. The memory may be removable, non-removable,or a combination thereof. Memory 920 may be implemented using hardwaredevices such as solid-state memory, hard drives, optical-disc drives,and the like. Computing environment 900 also includes one or moreprocessors 930 that read data from various entities such as memory 920,I/O interface 940, and network interface 950.

I/O interface 940 enables computing environment 900 to communicate withdifferent input devices and output devices. Examples of input devicesinclude a keyboard, a pointing device, a touchpad, a touchscreen, ascanner, a microphone, a joystick, and the like. Examples of outputdevices include a display device, an audio device (e.g. speakers), aprinter, and the like. These and other I/O devices are often connectedto processor 910 through a serial port interface that is coupled to thesystem bus, but may be connected by other interfaces, such as a parallelport, game port, or universal serial bus (USB). A display device canalso be connected to the system bus via an interface, such as a videoadapter which can be part of, or connected to, a graphics processorunit. I/O interface 940 is configured to coordinate I/O traffic betweenmemory 920, the one or more processors 930, network interface 950, andany combination of input devices and/or output devices.

Network interface 950 enables computing environment 900 to exchange datawith other computing devices via any suitable network. In a networkedenvironment, program modules depicted relative to computing environment900, or portions thereof, may be stored in a remote memory storagedevice accessible via network interface 950. It will be appreciated thatthe network connections shown are exemplary and other means ofestablishing a communications link between the computers may be used.

It is understood that the term circuitry used through the disclosure caninclude specialized hardware components. In the same or otherembodiments circuitry can include microprocessors configured to performfunction(s) by firmware or switches. In the same or other exampleembodiments circuitry can include one or more general purpose processingunits and/or multi-core processing units, etc., that can be configuredwhen software instructions that embody logic operable to performfunction(s) are loaded into memory, e.g., RAM and/or virtual memory. Inexample embodiments where circuitry includes a combination of hardwareand software, an implementer may write source code embodying logic andthe source code can be compiled into machine readable code that can beprocessed by the general purpose processing unit(s). Additionally,computer executable instructions embodying aspects of the invention maybe stored in ROM EEPROM, hard disk (not shown), RAM, removable magneticdisk, optical disk, and/or a cache of processing unit. A number ofprogram modules may be stored on the hard disk, magnetic disk, opticaldisk, ROM, EEPROM or RAM, including an operating system, one or moreapplication programs, other program modules and program data. It will beappreciated that the various features and processes described above maybe used independently of one another or may be combined in various ways.All possible combinations and sub-combinations are intended to fallwithin the scope of this disclosure.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements, and/orsteps. Thus, such conditional language is not generally intended toimply that features, elements and/or steps are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment. The terms “comprising,”“including,” “having,” and the like are synonymous and are usedinclusively, in an open-ended fashion, and do not exclude additionalelements, features, acts, operations, and so forth. Also, the term “or”is used in its inclusive sense (and not in its exclusive sense) so thatwhen used, for example, to connect a list of elements, the term “or”means one, some, or all of the elements in the list.

In an embodiment, a duplex system for acquiring images may comprise ascanning fiber endoscope comprising a probe with a single mode scanningfiber resonating with cantilever resonance along electronicallycontrolled scanning paths, and at least one computing device comprisinga memory in operable communication with at least one processor, thememory having instructions to cause the at least one processor to obtainone or more RGB surface image frames from the endoscope, obtain one ormore penetrating OCT cross-sectional image frames from the endoscope,and display duplex images by interleaving the one or more RGB surfaceimage frames and interleaving the one or more OCT cross-sectional imageframes.

In the embodiment, the memory may comprise instructions to further causethe at least one processor to construct a plurality of B-mode imagesfrom a plurality of A-line scans performed while obtaining the one ormore RGB surface image frames, each B-mode image offset by a scanningangle. In the embodiment, wherein interleaving includes interleaving theplurality of B-mode images to construct a three-dimensional image orpre-interventional volumetric survey. In the embodiment, wherein thethree-dimensional image is used to measure a volume of biologicalstructures.

In the embodiment, wherein the single mode scanning fiber within theprobe oscillates along a scanning path within a probe. In theembodiment, wherein the one or more OCT cross-section image framesidentify at least one of an occlusion, a calcification, adventitia, anda microchannel.

In an embodiment, a method for acquiring OCT B-mode images may compriseoscillating a cantilever scanning fiber within a probe along a scanningpath, wherein the probe is configured to obtain reflected lightgenerated by the scanning fiber, and the oscillating scanning pathincreases in amplitude over time, obtaining a plurality of A-line scansfrom the obtained reflected light, each A-line scan obtained at a pointalong the oscillating scanning path where a speed of the probe is at aminimum, and constructing a B-mode image from the plurality of A-linescans.

In the embodiment, wherein the oscillating scanning path is defined bytwo sinusoidal inputs.

In the embodiment, further comprising constructing a plurality of B-modeimages from the plurality of A-line scans, each B-mode image offset by ascanning angle. In the embodiment, further comprising interleaving theplurality of B-mode images to construct a three-dimensional image.

In the embodiment, wherein the probe is in a scanning fiber endoscope.

In an embodiment, a computer readable storage medium comprisinginstructions stored thereon that may cause a computing system to atleast oscillate a probe along a scanning path, the probe configured toobtain reflected light generated by the probe, the scanning pathincreasing in amplitude over time, obtain a plurality of A-line scansfrom the obtained reflected light, each A-line scan obtained at a pointalong the scanning path where a speed of the probe is at a minimum, andconstruct a B-mode image from the plurality of A-line scans.

In the embodiment, further comprising instructions to cause thecomputing system to at least: construct a plurality of B-mode imagesfrom the plurality of A-line scans, each B-mode image offset by ascanning angle.

In the embodiment, further comprising instructions to cause thecomputing system to at least construct a plurality of RGB images fromthe reflected light obtained while the probe moves along the scanningpath, and interleave the plurality B-mode images with the plurality ofRGB images to construct a duplex image.

In the embodiment, wherein the B-mode image depicts an area within ablood vessel lumen.

In the embodiment, wherein the B-mode image identifies an occlusionwithin a blood vessel.

While certain example embodiments have been described, these embodimentshave been presented by way of example only and are not intended to limitthe scope of the inventions disclosed herein. Thus, nothing in theforegoing description is intended to imply that any particular feature,characteristic, step, module, or block is necessary or indispensable.Indeed, the novel methods and systems described herein may be embodiedin a variety of other forms; furthermore, various omissions,substitutions and changes in the form of the methods and systemsdescribed herein may be made without departing from the spirit of theinventions disclosed herein. The accompanying claims and theirequivalents are intended to cover such forms or modifications as wouldfall within the scope and spirit of certain of the inventions disclosedherein.

What is claimed:
 1. A duplex system for acquiring images, comprising: ascanning fiber endoscope comprising a probe with a single mode scanningfiber resonating with cantilever resonance along electronicallycontrolled oscillating scanning paths; and at least one computing devicecomprising a memory in operable communication with at least oneprocessor, the memory having instructions to cause the at least oneprocessor to: obtain a plurality of RGB surface image frames from theendoscope, obtain a plurality of penetrating OCT cross-sectional imageframes from the endoscope, wherein each OCT cross-sectional image frameamong the plurality of OCT cross-sectional image frames is captured at apoint along the oscillating scanning paths where the scanning fiberreaches a minimum velocity, and display the plurality of RGB surfaceimage frames and the plurality of OCT cross-sectional image frames. 2.The system of claim 1, wherein the memory comprises instructions tofurther cause the at least one processor to construct a plurality ofB-mode images from a plurality of A-line scans performed while obtainingthe one or more RGB surface image frames, each B-mode image offset by ascanning angle.
 3. The system of claim 2, wherein the memory comprisesinstructions to further cause the plurality of B-mode images to be usedto construct a three-dimensional image or pre-interventional volumetricsurvey.
 4. The system of claim 3, further comprising, instructions tocause the at least one processor to use the three-dimensional image tomeasure a volume of biological structures.
 5. The system of claim 1,wherein the single mode scanning fiber oscillates along a scanning pathwithin the probe.
 6. The system of claim 1, wherein the one or more OCTcross-section image frames identify at least one of an occlusion, acalcification, adventitia, and a microchannel.
 7. The system of claim 1,wherein the memory comprises instructions to further cause the pluralityof RGB surface image frames to be interleaved and displayed as a firstimage of a duplex image and the plurality of OCT cross-sectional imageframes to be interleaved and displayed as a second image of the dupleximage.
 8. The system of claim 7, wherein the memory comprisesinstructions to further cause the at least one processor to construct aplurality of B-mode images from a plurality of A-line scans performedwhile obtaining the one or more RGB surface image frames, each B-modeimage offset by a scanning angle.
 9. The system of claim 8, wherein thememory comprises instructions to further cause the plurality of B-modeimages to be used to construct a three-dimensional image orpre-interventional volumetric survey.